Contractors working at the Pike River mine at the time of the explosion say management took 51 minutes to contact emergency services following last November’s first explosion and initially had no idea how many miners were underground.

Information released by contractors owed money by the mine shows Pike River also failed to tell miners’ families quickly enough, with some not contacted until the next day.

A group of 29 miners were killed in a series of explosions at the coal mine on the West Coast of New Zealand’s South Island, starting in November last year.

The men’s bodies have yet to be recovered and the mines owners Pike River Coal have been placed in receivership.

Contractors owed $5m by the mine have decided to file court action to have the company placed in liquidation.

At a meeting on Monday to discuss the move, the group talked about information collected in making that decision. They said it showed the families have been treated “despicably”.

“We have found a lot of information that is extremely disturbing,” the contractors’ spokesman Gerry Morris said.

“The communication and treatment of the families has been absolutely despicable.”

Morris, who is working with the contractors together with lawyers Greg King and David Butler, said at one point the mine company thought there may have been as many as 36 men trapped underground.

It took 51 minutes to contact emergency services, and 14 hours to contact some families.

The Mines Rescue Service was denied entry to the mine – a decision made during a conference call to Wellington, Morris said.

“Their records were completely inadequate and no respect was paid to the history of the mine. It’s just staggering.”

Mines safety manager and father of one of the victims, Neville Rockhouse, who was one of the people in the control room at the time of the disaster, said he wasn’t told a man had emerged from the mine.

However, criticisms that Mines Rescue should have gone into the mine straight away needed to be answered by the Royal Commission.

“If we had sent them down at that time when our gas monitoring system had been blown to bits we could have had a situation… like walking down the barrel of a gun when someone’s got their finger on the trigger.”

Rockhouse said he agreed with the contractors’ criticism that the families should have been shown a video of the first blast sooner.

“I think had we seen that video in the first day or two we would have all been destroyed emotionally,” he said.

If the group had then been given a better explanation of the video and had better understood perhaps the mine could have been sealed earlier, he said.

“And that would have led to no future explosions and we wouldn’t be going through the torture we are now.”